Margaret J Stern

US Patent:

6413781, Jul 2, 2002

Filed:

Apr 6, 1999

Appl. No.:

09/287591

Inventors:

Michael W. Geis - Acton MA
Roderick R. Kunz - Acton MA
Margaret B. Stern - Sudbury MA

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

G01N 2500

US Classification:

436178, 436177, 436157, 210767, 210774, 210775, 210149, 210176, 422101

Abstract:

The method and apparatus of the invention create a dynamic Soret effect for propelling a target chemical constituent along a pathway. A moving temperature profile impressed upon the pathway produces consecutive alternating warmer and cooler zones along the path which transport components of a mixture down the path according to their respective diffusivities. In one embodiment, the invention provides a dynamic thermophoretic concentrator for separating a target chemical constituent from a mixture of components on the basis of diffusion coefficient by using alternate forward and backward motion of a temperature profile along the pathway, thereby accumulating an ultimate concentration of the target constituent greater than its initial concentration in the mixture.

US Patent:

6731438, May 4, 2004

Filed:

Nov 29, 2000

Appl. No.:

09/725354

Inventors:

Margaret B. Stern - Sudbury MA
Zong Long Liau - Belmont MA

Assignee:

Axsun Technologies, Inc. - Billerica MA

International Classification:

G02B 2702

US Classification:

359804, 359808, 359811, 2504922, 430 22

Abstract:

A technique for creating alignment feature in mass transported substrates yields alignment features that can be located with high degrees of accuracy. Specifically, structures such as concave or convex lenses are created that yield a light pattern in transmission or reflection when the part of the substrate is imaged or a plane near the substrate is imaged. This light pattern is then used to align the substrate during subsequent lithography or packaging processes.

US Patent:

6768756, Jul 27, 2004

Filed:

Mar 12, 2001

Appl. No.:

09/804618

Inventors:

Dale C. Flanders - Lexington MA
Steven F. Nagle - Cambridge MA
Margaret B. Stern - Sudbury MA

Assignee:

Axsun Technologies, Inc. - Billerica MA

International Classification:

H01S 313

US Classification:

372 43, 372 29022, 372 75, 372 99, 372101

Abstract:

An optical membrane device and method for making such a device are described. This membrane is notable in that it comprises an optically curved surface. In some embodiments, this curved optical surface is optically concave and coated, for example, with a highly reflecting (HR) coating to create a curved mirror. In other embodiments, the optical surface is optically convex and coated with, preferably, an antireflective (AR) coating to function as a refractive or diffractive lens.

US Patent:

7124928, Oct 24, 2006

Filed:

Jan 16, 2001

Appl. No.:

09/761514

Inventors:

Steven D. Conover - Chelmsford MA, US
Randal A. Murdza - North Andover MA, US
Margaret A. Stern - Sudbury MA, US

Assignee:

Axsun Technologies, Inc. - Billerica MA

International Classification:

B23K 31/02
G02B 7/00

US Classification:

228103, 228105, 359819

Abstract:

A micro-optical train manufacturing process includes a step of characterizing the position of optical components on an optical bench, typically using a metrology system. These optical components are then aligned with respect to each other in a passive alignment step based on data from the metrology system and optical system design information. As a result, a subsequent active align process can be avoided in some situations, or if a subsequent active alignment process is performed, the time required for that active alignment process can be reduced because of this initial metrology-based passive alignment step.

US Patent:

7208333, Apr 24, 2007

Filed:

May 8, 2004

Appl. No.:

10/840814

Inventors:

Dale C. Flanders - Lexington MA, US
Steven F. Nagle - Cambridge MA, US
Margaret B. Stern - Sudbury MA, US

Assignee:

Axsun Technologies, Inc. - Billerica MA

International Classification:

H01L 21/00

US Classification:

438 29, 257E31127

Abstract:

An optical membrane device and method for making such a device are described. This membrane is notable in that it comprises an optically curved surface. In some embodiments, this curved optical surface is optically concave and coated, for example, with a highly reflecting (HR) coating to create a curved mirror. In other embodiments, the optical surface is optically convex and coated with, preferably, an antireflective (AR) coating to function as a refractive or diffractive lens.

US Patent:

20020011201, Jan 31, 2002

Filed:

Jul 18, 2001

Appl. No.:

09/908237

Inventors:

Margaret Stern - Sudbury MA, US

Assignee:

AXSUN Technologies, Inc.

International Classification:

C30B028/12
C30B023/00
C30B028/14
C30B025/00

US Classification:

117/084000

Abstract:

An apparatus and method for creating a supply of group V vapor required for various material processing applications such as crystal growth or the mass transport process, when applied to III-V materials (e.g., GaP) comprises a stable source of group V material (e.g., a GaP wafer), a process tube, and inner tube, a three-zone furnace incorporating a cold trap zone for the group III material, and a “loose” plug for the process tube. The phosphorus vapor is generated by using a source GaP wafer placed at a higher temperature than that of the main process wafer in the mass transport process. When high phosphorous vapor concentration is desired, other solid sources such as InP or red P can be used. To minimize vapor loss to the ambient, both wafers are enclosed in a quartz tube equipped with a quartz plug. However, the source wafer generates not only phosphorus but also gallium vapor. The latter interferes with mass transport and needs to be filtered out. This is conveniently accomplished by employing a larger (longer) process tube and by further placing the source in a smaller inner tube within the main process tube. The source inner tube first directs the vapor to a cooler region, where gallium is selectively condensed out before it reaches the process wafer.

US Patent:

50213636, Jun 4, 1991

Filed:

Sep 7, 1989

Appl. No.:

7/404237

Inventors:

Harry F. Lockwood - Waban MA
Margaret B. Stern - Sudbury MA
Marvin Tabasky - Peabody MA
Victor Cataldo - Wilmington MA

Assignee:

Laboratories Incorporated - Waltham MA

International Classification:

H01L 2144

US Classification:

437200

Abstract:

Method of forming conductive members on a substrate of GaAs. Silicon is placed on the substrate surface in the desired pattern of the conductive members. The substrate is exposed to a gaseous atmosphere containing WF. sub. 6. WF. sub. 6 is reduced by the silicon causing tungsten to selectively deposit on the silicon but not on the exposed GaAs. The substrate is given a rapid thermal annealing treatment which causes the silicon-tungsten elements to form conductive members having a silicon rich layer at the bottom, an intermediate tungsten silicide layer, and a tungsten rich layer at the top. The conductive members form ohmic contacts with underlying heavily doped GaAs and rectifying Schottky barrier contacts with underlying lightly doped GaAs.

US Patent:

51631083, Nov 10, 1992

Filed:

Aug 2, 1991

Appl. No.:

7/739587

Inventors:

Craig A. Armiento - Acton MA
Chirravuri Jagannath - Medfield MA
Marvin J. Tabasky - West Peabody MA
Thomas W. Fitzgerald - Framingham MA
Harry F. Lockwood - Waban MA
Paul O. Haugsjaa - Acton MA
Mark A. Rothman - Acton MA
Vincent J. Barry - Framingham MA
Margaret B. Stern - Sudbury MA

Assignee:

GTE Laboratories Incorporated - Waltham MA

International Classification:

G02B 642

US Classification:

385 89

Abstract:

A method of passively aligning optical receiving elements such as fibers to the active elements of a light generating chip includes the steps of forming two front and one side pedestal structures on the surface of a substrate body, defining a vertical sidewall of the chip to form a mating channel having an edge at a predetermined distance from the first active element, mounting the chip epi-side down on the substrate surface, and positioned the fibers in fiber-receiving channels so that a center line of each fiber is aligned to a center line of a respective active element. When mounted, the front face of the chip is abutting the contact surfaces of the two front pedestals, and the defined sidewall of the mating channel is abutting the contact surface of the side pedestal. The passive alignment procedure is also effective in aligning a single fiber to a single active element.